1. Field of the Invention
This invention relates to an electromagnetically operated device having a sensor for monitoring the magnetic field for controlling power admitted to the coil of the device.
2. Description of the Prior Art
Electromagnetically operated devices such as large relays and contactors consume much more power to close an armature than is required to maintain the armature closure. As a result excess power is consumed which is indicated by vibration between the armature and stator as well as heating of the pull-in coil. It has been recognized that when an armature is closed on a stator, the power required to maintain the device in the closed position could be reduced to conserve power, reduce vibration, and reduce heating of the coil.